refactor(ui/templates): drop row kebabs; double-click opens templates

The right-click context menu is now the single entry point for every
per-row action — folders, templates, and composition leaves. Drop the
⋮ kebab buttons that duplicated the menu and the click-to-open
behavior that was easy to trigger by accident while navigating the
tree. Templates and composition slots open on double-click instead.

- RenderNodeKebab removed entirely.
- Selectable / SelectedKeyChanged / OnTreeNodeSelected dropped from
  the TreeView wiring — single-click no longer navigates.
- New OpenTemplate(id) helper bound to @ondblclick on Template and
  Composition labels.

src/ScadaLink.CentralUI/Components/Pages/Design/Templates.razor

@@ -83,9 +83,7 @@
                       ChildrenSelector="n => n.Children"
                       HasChildrenSelector="n => n.Kind != TmplNodeKind.Composition && n.Children.Count > 0"
                       KeySelector="n => (object)n.Key"
-                      StorageKey="templates-tree"
+                      StorageKey="templates-tree">
-                      Selectable="true"
-                      SelectedKeyChanged="OnTreeNodeSelected">
                 <NodeContent Context="node">
                     @RenderNodeLabel(node)
                 </NodeContent>
@@ -234,6 +232,9 @@
 
     private TreeView<TmplNode> _tree = default!;
 
+    private void OpenTemplate(int templateId) =>
+        NavigationManager.NavigateTo($"/design/templates/{templateId}");
+
     private RenderFragment RenderNodeLabel(TmplNode node) => __builder =>
     {
         switch (node.Kind)
@@ -249,83 +250,23 @@
                         <span class="badge rounded-pill bg-secondary-subtle text-secondary-emphasis">@node.Children.Count</span>
                     </span>
                 }
-                @RenderNodeKebab(node)
                 break;
 
             case TmplNodeKind.Template:
                 <span class="tv-glyph"><i class="bi bi-file-earmark-text"></i></span>
                 <span class="tv-label @(node.Children.Count > 0 ? "fw-semibold" : "")"
-                      title="@node.Label">@node.Label</span>
+                      title="@node.Label"
-                @RenderNodeKebab(node)
+                      @ondblclick="() => OpenTemplate(node.EntityId)">@node.Label</span>
                 break;
 
             case TmplNodeKind.Composition:
                 <span class="tv-glyph"><i class="bi bi-arrow-return-right"></i></span>
-                <span class="tv-label" title="@node.Label">@node.Label</span>
+                <span class="tv-label" title="@node.Label"
-                @RenderNodeKebab(node)
+                      @ondblclick="() => OpenTemplate(node.Composition!.ComposedTemplateId)">@node.Label</span>
                 break;
         }
     };
 
-    private RenderFragment RenderNodeKebab(TmplNode node) => __builder =>
-    {
-        <span class="tv-kebab dropdown ms-auto" @onclick:stopPropagation="true">
-            <button type="button"
-                    class="btn btn-link btn-sm p-0 px-1 text-secondary tv-kebab-toggle"
-                    data-bs-toggle="dropdown"
-                    aria-expanded="false"
-                    aria-label="@($"More actions for {node.Label}")">
-                <i class="bi bi-three-dots-vertical"></i>
-            </button>
-            <ul class="dropdown-menu dropdown-menu-end">
-                @switch (node.Kind)
-                {
-                    case TmplNodeKind.Folder:
-                        <li><button class="dropdown-item" @onclick="() => OpenNewFolderDialog(node.EntityId)">New Folder</button></li>
-                        <li><button class="dropdown-item" @onclick='() => NavigationManager.NavigateTo($"/design/templates/create?folderId={node.EntityId}")'>New Template</button></li>
-                        <li><button class="dropdown-item" @onclick="() => OpenRenameFolderDialog(node.EntityId, node.Label)">Rename</button></li>
-                        <li><button class="dropdown-item" @onclick="() => OpenMoveFolderDialog(node.EntityId, node.Label)">Move to Folder…</button></li>
-                        <li><hr class="dropdown-divider" /></li>
-                        <li><button class="dropdown-item text-danger" @onclick="() => DeleteFolder(node.EntityId, node.Label)">Delete</button></li>
-                        break;
-
-                    case TmplNodeKind.Template:
-                        <li><button class="dropdown-item" @onclick='() => NavigationManager.NavigateTo($"/design/templates/create?parentId={node.EntityId}")'>New Inheriting Template</button></li>
-                        <li><button class="dropdown-item" @onclick="() => OpenComposeDialog(node.Template!)">Compose into…</button></li>
-                        <li><button class="dropdown-item" @onclick="() => OpenMoveTemplateDialog(node.EntityId, node.Label)">Move to Folder…</button></li>
-                        <li><hr class="dropdown-divider" /></li>
-                        <li><button class="dropdown-item text-danger" @onclick="() => DeleteTemplate(node.Template!)">Delete</button></li>
-                        break;
-
-                    case TmplNodeKind.Composition:
-                        <li><button class="dropdown-item" @onclick='() => NavigationManager.NavigateTo($"/design/templates/{node.Composition!.ComposedTemplateId}")'>Open composed template</button></li>
-                        <li><button class="dropdown-item" @onclick="() => RenameComposition(node.Composition!)">Rename…</button></li>
-                        <li><hr class="dropdown-divider" /></li>
-                        <li><button class="dropdown-item text-danger" @onclick="() => DeleteComposition(node.Composition!)">Delete</button></li>
-                        break;
-                }
-            </ul>
-        </span>
-    };
-
-    private void OnTreeNodeSelected(object? key)
-    {
-        if (key is not string s) return;
-        if (s.StartsWith("t:") && int.TryParse(s[2..], out var tid))
-        {
-            NavigationManager.NavigateTo($"/design/templates/{tid}");
-        }
-        else if (s.StartsWith("c:") && int.TryParse(s[2..], out var cid))
-        {
-            var comp = _templates.SelectMany(t => t.Compositions).FirstOrDefault(c => c.Id == cid);
-            if (comp != null)
-            {
-                NavigationManager.NavigateTo($"/design/templates/{comp.ComposedTemplateId}");
-            }
-        }
-        // Folder selection is intentionally a no-op (use right-click for folder actions).
-    }
-
     private RenderFragment RenderNodeContextMenu(TmplNode node) => __builder =>
     {
         switch (node.Kind)